Folding rule with spring-joints.



No. 884355.. PATENTED APR. 7, 1908.-

- E..- ZWBIGLER.

FOLDING RULE WITH SPRING JOINTS.

APPLICATION FILED SEPT.16,1907.

W V I Zciu are? ,zwczy'ier 1w: NORRIS PETERS 50., wAsHJnnroN, n, c.

EDUARD ZWEIGLER, OF EISENAGH, GERMANY, ASSIGNOR. TO HORSELWER GERMANY.

FOLDING RULE WITH SPRING-JOINTS.

Specification of Letters Patent.

Application filed. September 16, 1907.

Patented April 7, 1908.

Serial No. 393,084.

To aZZ whom it may concern.

Be it known that I, EDUARD ZWEIGLER,

workmaster, a subject of the King of Saxony,

residing at Eisenach, Grand Duchy of Saxe WVeimar-Eisenach, Germany, have invented certain new and useful Improvements in Folding Rules with Spring-Joints, of which the following is a specification.

In the case of the known folding rules with spring joints, having either visible pivots, as shown in Figure 1 of the drawing, or covered pivots as shown in Fig. 2, the lateral edges of the rule members at both sides of the visible or covered pivot are beveled or cut away, as shown at a, so that the division marks are interrupted and do not extend to the edges. This prevents the marking of accurate measurements with the respective parts of the rule, and the user is compelled to rely mainly on his own judgment when that part of the scale is required. In the case of these known folding rules with spring joints the beveling of the edges of the interconnected {members is absolutely necessary to allow of dove-tailing the spring mounts on the members in order to give them a good hold and revent relative displacement, abutments for the mounts being fproduced by the beveling or cuttin away 0 the edges. To prevent WithdrawaTof the rule members from the mounts, lugs b or the like (Fig. 2) are punched out of the wider parts of the latter and are pressed into the wooden members by mechanical means. Absolute security against longitudinal displacement is not afforded by this arrangement, owing to the fact that the lugs are only formed on the Wider parts of the mounts.

In order to obviate the disadvantage of an interrupted scale at the edges of the rule members with spring joint, the present invention provides that the lateral edges of the said members are not cut away or beveled at cny part but have the same width throughout. The cost of manufacture is reduced by dispensing with the expensive 0 eration of beveling or cutting away the e ges. This construction, without beveled edges, can be adopted both in the case of spring oint folding rules with visible pivots, as shown in Fi 1, and in the case of spring joint fOldiIlg ruFes with covered pivots, as shown in Fig. 2.

The folding rule with spring joint provided by the present invention is therefore novel and distinguished by the fact that the scale is visible in its entirety and not, as hitherto, interrupted by beveled edges provided for holding the mounts. For this purpose the mounts of the spring joints engage or penetrate the material of the rule members at the narrow sides of the latter. Figs. 3, 4 and 5 show, by way of example, a form of construction of a spring joint folding rule of this kind in plan view, cross-section and side view respectively. From these drawings it will be seen that the scale divisions extend at all parts to the edges 0 of the rule members and are not interrupted, and that relative longitudinal displacement of the pivotally connected members is nevertheless effectively prevented owing {to the fact that the rectangularly bent or flanged edges f of the mounts d are provided along their entire length with teeth 9 which penetrate into the rule members.

As shown in Figs. 6 and 7, the same purpose can also be effected by bending inwards the longitudinal edges of the flanges f and pressing the ribs h thus formed into the lateral surfaces of the rule members. In order to prevent splitting of the wood, the said members may be previously provided with longitudinal grooves for the insertion of the edges 71 In the third form of construction shown in Figs. 8 and 9 the lugs 71 which engage the rule members are punched out of the rectan- KE, OF EISENACH,

gularly bent flanges f of the mounts d.

These methods of fixing the mounts insure absolutely rigid connection of the same tothe rule members, and also the exact alinement of the members relatively to each other, so that the members are fitted together with great accuracy. Relative lon itudinal displacement of the members is e 'ectively prevented, and also lateral displacement of the mounts, such as occurs if the beveling of the edges has not been carried out with suificient accuracy. The result of the improved construction is to provide a rule of great strength which is not weakened at the part subjected to the greatest strain. In the case of the rules with spring joints shown in Figs. 1 and 2 a weakening of the wood is involved by the fact that the bevelin of the edges at a is bounded by deep laterzfi incisions. In the improved rule the mounts cl laterally engage the rule members by means of numerous small teeth, lugs or the like which provide suflicient resistance to the lateral ressure applied during the folding and unfo ding of the rule.

Claims:

1. A rule embodying foldable sections, and cooperating pivot plates for connecting the respective sections, the said plates being provided with flanges that cooperate with the longitudinal edges of the respective sections, and securing portions extending inwardly into the material composing the said edges of the sections.

2. A foldable rule embodying cooperating sections, and pivot plates for connecting the sections, each plate being provided with oppositely arranged flan es bent to engage flatwise the longitudina edges of the respective section, and securing devices on said flanges projecting into the material composing the edges of the section in a plane parallel to the plane of movement of the sections.

3. A rule comprising foldablesections, and cooperating pivot plates, each of the latter being provided with a pair of lateral flanges formed at the opposite longitudinal edges of the plate, and pointed securin devices formed integral with each flange, t is securing devices on one flange being directed toward those on the opposite flange and engaging the material composing the longitudinal edges of the section.

4. A rule comprising flat foldable sections, and cooperating pivot plates arranged on the respective sections, each. plate having a pair of parallel longitudinal flanges adapted to overlap and cooperate with the narrow longitudinal edges of its respective section,

and the edge of each flange being turned in Wardly and embedded in the material at the narrow edge of each section.

5. A rule comprising flat r'oldable sections, and cooperating pivot plates for connecting the respective sections, each plate having a pair of oppositely arranged flanges which overlap and cooperate with the corresponding longitudinal edges of its respective section, and the edge of each flange being turned inwardly in alinement with the edge of the flange at the opposite side of the respective plate and provided with a row of sharpened projections which engage in the material at the narrow edge of the section.

6. A rule comprising flat foldable sections, and cooperating pivot plates for connecting the respective sections, each plate havin a body portion arranged on one of the at sides of its respective section and provided with a pair of parallel flanges bent laterally at right angles to the body portion of the plate, the flanges being of a length less than the thickness of the section, and having rows of sharpened rojections which are turned inwardly in a inement with one another and in a plane parallel to the plane of the body of the plate, the said projections being embedded in the material at the narrow edges of the section.

In testimony whereof I have hereunto set hand in presence of two subscribing wit IlGSSOS.

EDUARD ZWEIGLER. Witnesses:

EDWARD RA UnT, PAUL MALZER. 

